package com.ikaros.concurrency.example.commonUnsafe;

import lombok.extern.slf4j.Slf4j;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;

/**
 * so
 * stringBuilder 线程不安全
 * stringBuffer线程安全
 */
@Slf4j
public class StringBuilderAndStringBuffer {
    //请求总数
    private static int clientTotal = 5000;
    //并发执行的线程数
    private static int threadTotal = 200;

    private static StringBuilder stringBuilder = new StringBuilder();
    private static StringBuffer stringBuffer = new StringBuffer();


    public static void main(String[] args) throws Exception {
        ExecutorService executorService = Executors.newCachedThreadPool();
        final Semaphore semaphore = new Semaphore(threadTotal);
        final CountDownLatch countDownLatch = new CountDownLatch(clientTotal);
        for (int i = 0; i < clientTotal; i++) {
            executorService.execute(() -> {
                try {
                    semaphore.acquire();
                    addStringBuilder();
                    semaphore.release();
                } catch (Exception e) {
                    log.error("exception", e);
                }
                countDownLatch.countDown();
            });
        }
        countDownLatch.await();
        executorService.shutdown();
        log.info("stringBuilder:{}", stringBuilder.length());
        log.info("stringBuffer:{}", stringBuffer.length());
    }

    private static void addStringBuilder() {
        stringBuilder.append("1");
        stringBuffer.append("1");
    }
}
